1. Field of the Invention
The present invention relates to sealed odor traps for waterless urinals, anti-evaporation floor drain traps and, more particularly, to improvements in the internal structure of oil-sealed odor traps for prolonging sealant retention and for protection against high pressure water flushing.
2. Description of Related Art and Other Considerations
With increasing emphasis on water conservation, there is continuing interest in toilets and urinals designed to minimize the amount of water consumed in flushing, to mitigate excessive demands on both water supplies and wastewater disposal systems, both of which have tended to become overloaded with increasing populations.
Sanitation codes require urinals to provide an odor seal to contain gasses and odors which develop in the drain system; this function is conventionally performed by the well known P-trap or S-trap in which the seal is formed by a residual portion of the flushing water. This seal effectively provides a barrier to sewer odors from passing from the drainpipe beyond the trap. However, the upward-facing liquid surface communicates freely with the user environment and, therefore, the trap must be kept free of residual urine by copious flushing to prevent unacceptable odor levels from the liquid in the trap. As a result, a large amount of water is consumed in flushing these conventional urinals. Especially in the United States over many years when water was cheap and plentiful, conventional flushing type urinals and water-wasteful toilets held an unchallenged monopoly. However, more recently, threatened and real water shortages have aroused new environmental concerns and heightened conservation awareness as evidenced by the introduction of low flush toilets.
As the cost of water increases and budgets tighten, the prospect of a viable waterless urinal system becomes extremely attractive to a wide range of public agencies, cities, states, penal institutions, defense establishments, recreational and parks departments and the like. Waterless urinals utilizing oil-sealed odor traps are becoming viable. However, the present inventor has discovered that a key factor in their potential is the attainment of low maintenance, and that this is largely dependent on the longevity of the liquid sealant which, in turn, is related to the internal structure of the odor trap. Thus, the present inventor has recognized that improvements are desirable both in the rate of depletion under normal service conditions and in protection against catastrophic sealant loss due to high pressure water flushing which, though not required, can occur inadvertently.
Known prior art is listed, as follows.
List of ReferencesPatent No:Patentee:  303,822D'Heureuse1,050,290Posson3,829,909Rod, et al.4,026,317Ekstrom4,028,747Newton4,045,346Swaskey4,244,061Webster, et al.4,263,934Redden, et al.4,411,286Ball4,432,384Guiboro4,773,441Biba5,159,724Vosper5,203,369Hwang   318264ZeiglerGermany    2816597.1ErnstGermany  606,646ErnstSwitzerlandStatement of the Prior Art
U.S. Pat. No. 303,822 (D'Heureuse) discloses a wastewater pipe S-trap into which a disinfectant or deodorizer is introduced.
The use of an oil as a recirculated flushing medium in a toilet system is disclosed in U.S. Pat. No. 3,829,909 (Rod, et al.).
The use of oil in toilets to form an odor trap is disclosed in German Patent No. 121356 (Beck, et al.) and in U.S. Pat. Nos. 1,050,290 (Posson) and 4,028,747 (Newton).
Bell traps, essentially a coaxial form of S-trap, have been known for over a century; a popular form is exemplified in German Patent No. 318264 (Zeigler). A multiple baffle structure is disclosed in U.S. Pat. No. 4,026,317 (Ekstrom). Center-entry coaxial trap configurations are shown in U.S. Pat. Nos. 4,045,346 (Swaskey) and 5,203,369 (Hwang).
Beetz introduced an oily liquid layer floating in the trap as an odor barrier through which urine and water can permeate downward. Beetz makes the oil mixture have disinfectant properties and to have “innate adhesion power to attach itself to the odor lock parts so that the latter cannot be attacked by urine”. The Beetz disclosure includes daily maintenance, including cleaning, and coating the cast iron parts of the urinal, including the housing of the odor trap, with the oil mixture that “the oil has the property that said parts absorb so much of it that the oil film somehow repels the urine”. Beetz' requirement for daily cleaning and maintenance dictates an easily-disassembled-three piece structure with a leakage-prone bottom interface joint, and this requirement for the sealant to also act as a disinfectant is now believed to have caused excessive depletion of the sealant.
Other examples of oil-sealed traps are found in German Patent No. 2816597.1, and Swiss Patent No. 606,646 (Ernst), practiced under the trademark SYSTEM-ERNST.
The foregoing examples of traps found limited use in Europe. Typically, they are utilized in a “low flush” rather than a “waterless” manner, e.g. the Beetz patent was classified under water pipe lines, and the specification thereof refers to “water and urine”. The odor trap is mounted beneath the floor level and set in a concrete swale, functioning as an occasionally-flushed trough type or stall urinal of a type which is no longer recognized in United States building and sanitation codes.
A flushless urinal disclosed in U.S. Pat. No. 4,244,061 (Webster, et al.) uses no oil, but instead relies on a small “plug flow” entrance opening associated with a P-trap, and is based on the premise that “the urine in the trap during normal use will be fresh and therefore without unpleasant odor.”
A unitized cylindrical cartridge odor seal for a waterless urinal is disclosed by the present inventor as a joint inventor in U.S. patent application Ser. No. 08/052,668 filed 27 Apr. 1993 and in a continuation-in-part thereof Ser. No. 08/512,453 filed 8 Aug. 1995, in the category of an oil-sealed coaxial edge-entry trap having a cap part with an attached downward-extending tubular vertical partition.
A key parameter of oil-sealed odor traps for waterless urinals is the amount of sealant depletion that takes place under normal service conditions over periods of time and frequency of usage. Related to this is the possible partial or complete loss of sealant due to the abnormal condition of unnecessary but unavoidable high pressure flushing with water. While some modern oil-sealed odor traps are considerably improved over early versions, there remains an unfulfilled need for further improvements in the above-described aspects of sealant preservation; such improvements are provided by the present invention.